Phosphoinositide-based switches in endocytic membrane traffic and signaling. Membrane traffic and cell signaling are regulated by phosphoinositide (PIP)-based functional switches. How such PIP switches operate in space and time in most cases is unknown. The project provides elaborate chemical tools and molecular biological approaches that enable the dissection of PIP-based switches in endocytic and endosomal membrane traffic and their role in growth factor and nutrient signaling. These studies will provide new insights into the mechanisms underlying PIP-based functional switches and how dysfunction of such switches may lead to disease.